http://archive.freep.com/VideoNetwork/2240129651001/The-Duchess-of-Cambridge-Joins-the-Queen-to-Celebrate-150-Years-of-the-Tubehttp://cdn.newslook.com/2e/2e6ce504af3c428e3db84fa61581b0c2/mp4_low/2e6ce504af3c428e3db84fa61581b0c2-mp4_low.mp4http://archive.freep.com/VideoNetwork/2240129651001/The-Duchess-of-Cambridge-Joins-the-Queen-to-Celebrate-150-Years-of-the-Tubehttp://cdn.newslook.com/2e/2e6ce504af3c428e3db84fa61581b0c2/images/frame_0002.jpgThe Duchess of Cambridge Joins the Queen to Celebrate 150 Years of the TubePregnant Kate Middleton continued to showcase her maternity style as she accompanied the Queen on an official royal outing to mark the 150th anniversary of the London Underground.131Elizabeth IIKate MiddletonnewslookUnited KingdomLondonentertainment00:39